1. Field of the Invention
The present invention relates to a cassette loading mechanism of a magnetic recording and reproducing apparatus and particularly to a cassette loading mechanism of a magnetic recording and reproducing apparatus in which a plurality of types of cassettes with different sizes containing a magnetic tape as a magnetic recording medium can be selectively loaded for recording and reproduction.
2. Description of the Background Art
There are plural types of cassettes of different sizes containing magnetic tapes as magnetic recording media. In order to load various cassettes of different sizes for recording and reproduction, magnetic recording and reproducing apparatus such as video tape recorders (VTR's) corresponding to the respective sizes of the cassettes are used. If recording or reproduction is to be carried out on a small-sized cassette by using a large-sized cassette VTR, a cassette adapter is used to load the small-sized cassette in a recording or reproduction position for the large-sized cassette.
The inventors of the present application disclosed an invention of a cassette loading mechanism capable of selectively loading plural types of cassettes of different sizes to carry out recording and reproduction, in Japanese Patent Application No. 62-198415 filed on Aug. 7, 1987 (Patent Laying-Open No. 64-42051) and U.S. Pat. application Ser. No. 171,746 with claim to priority on the basis of the above mentioned Japanese Patent Application. According to the cassette loading mechanism proposed in the above mentioned invention, a large-sized cassette and a small-sized cassette can be selectively loaded for recording and reproduction without using a cassette adapter.
FIGS. 1 and 2 are left side views of a cassette control unit of a VTR of the above mentioned background art (taken from the direction of insertion of a cassette). In principle, the right side views are mechanically identical to those views.
Referring to FIGS. 1 and 2, a guide plate 7 is provided with two L-shaped grooves 7a, 7b and two straight grooves 7c, 7d. This guide plate 7 is fixed to a main chassis 12 of the VTR by means of two fixation screws 13. A drive gear 8 and a drive arm 9 are fixed to the guide plate 7, rotatably around the same shaft. A loading gear 10 and a loading arm 11 are fixed to the guide plate 7, rotatably around the same shaft.
A slider 6 is provided with a first guide shaft 6a and a second guide shaft 6b on each of its two sides. The first and second guide shafts 6a and 6b are inserted in the L-shaped grooves 7a and 7b, respectively, of the guide plate 7. The second guide shaft 6b is also inserted in a U-shaped groove 9a of the drive arm 9.
An adapter chassis 14 is provided with four adapter guide shafts 14a on each of its two sides. Respective two adapter guide shafts 14a are inserted in each of the straight grooves 7c and 7d of the guide plate 7. Further, a loading shaft 14b is provided on the adapter chassis 14. The loading shaft 14b is provided rotatably in the loading arm 11.
Though not shown, the right and left driver gears 8 have phase gears to be rotated with the same phase. The right and left loading gears 10 are also provided with phase gears to be rotated with the same phase. A cassette cover 15 for small-sized cassette is attached to the guide plate 7 rotatably around a cover support shaft 7e. The cassette cover 15 is actuated toward a closing direction by a return spring 16.
FIGS. 3 and 4 are schematic views showing the components of the adapter chassis 14 as the insertion portion for a small-sized cassette 1. The adapter chassis 14 has a first housing arm 17 rotatable around a shaft 17a at an intersection therebetween. An end of a second housing arm 18 is attached slidably to an elongate hole 14c of the adapter chassis 14. The first housing arm 17 and the second housing arm 18 are engaged with each other rotatably at their central portions. The first and second housing arms 17 and 18 are further attached rotatably to a housing 19. An up spring 20 is attached to the first and second housing arms 17 and 18. This enables the housing 19 to be raised.
Referring to FIG. 1, in the case of loading a large-sized cassette 3 into the VTR, when the large-sized cassette 3 is manually inserted into a slider (as shown in FIG. 5), the cassette 3 is pressed fixedly against the slider 6 by means of a cassette spring 4 attached to the slider 6. A loading start switch (not shown) detects the large-sized cassette 3, thereby driving a drive motor (not shown). Thus, the drive gear 8 and the drive arm 9 are rotated in the direction shown by the arrow A. By this rotation, the second guide shaft 6b is driven. The slider 6 is guided along the two L-shaped grooves 7a and 7b of each guide plate 7 and moves horizontally. After that, the slider 6 lowers vertically to a position shown by 6P. Thus, the loading of the large-sized cassette 3 into the VTR is completed.
In the case of ejecting the large-sized cassette 3, the motor (not shown) is rotated reversely and the operation opposite to the above described operation is carried out, whereby the large-sized cassette 3 is taken out.
Referring to FIGS. 1 and 2, in the case of the small-sized cassette 1 into the VTR, when the small-sized cassette 1 is manually inserted into the housing 19, the cassette 1 is fixed in the housing 19 under pressure of a cassette spring 21 attached to the housing 19. The position of the housing 19 on this occasion is shown in FIG. 1. When the housing 19 is pushed downward, the housing 19 is moved to a position shown in FIG. 2. Then, by means of a lock mechanism (not shown) of the adapter chassis 14, the housing 19 is fitted and locked in the adapter chassis 14. Then, an insertion detection switch and a lock detection switch (both not shown) for the small-sized cassette 1 detect the locked state of the housing 19 where the small-sized cassette 1 is inserted. A housing motor (not shown) drives a first tape drawing-out arm 22 and a second tape drawing-out arm 23. As a result, a magnetic tape 1a is drawn out to a prescribed position 1d (as shown in FIG. 4). The first and second tape drawing-out arms 22 and 23 have their respective top ends provided with rotatable rollers and those arms are attached rotatably to the adapter chassis 14. At the same time as the above mentioned drive, the drive motor (not shown) is driven. As a result, in the same manner as in the case of loading the large-sized cassette 3, the slider 6 moves to the position 6P for recording and reproduction. After detection of the magnetic tape 1a drawn out to the prescribed position 1d and the slider 6 moved to the position 6P for recording and reproduction, a loading motor (not shown) is driven. Thus, the loading gears 10 and the loading arms 11 are rotated in the direction shown by the arrow B. Accordingly, the entire body of the adapter chassis 14 is guided by means of the adapter guide shaft 14a and the two straight grooves 7c, 7d of each guide plate 7, so that it is lowered while it is maintained horizontal. As a result, the entire body of the adapter chassis 14 is loaded on the slider 6 which has been moved to the position 6P for recording and reproduction. The adapter chassis 14 is moved to a position shown by 14Q. As shown in FIG. 5, any top plate is not provided on the slider 6. On the other hand, as shown in FIGS. 3 and 4, the adapter chassis 14 has slider escape holes 14d so that the first and second guide shafts 6a and 6b of the slider 6 may not interfere with the cassette spring 4. As a result, the adapter chassis 14 contacts four positioning shafts 12a, 12b, 12c and 12d without any gap.
As shown in FIG. 4, the small-sized cassette 1 is provided with a feed reel 1b and a rewind reel 1c. The magnetic tape 1a is wound on the feed reel 1b and the rewind reel 1c. The rewind reel 1c has a hub portion provided with a gear. A drive gear 2c attached rotatably to the adapter chassis 14 engages with the rewind reel 1c. The drive gear 2c engages with a drive reel 2d. The magnetic tape 1a is wound and rewound by driving the drive reel 2d and the feed reel 1b by means of a reel motor (not shown).
In order to eject the small-sized cassette 1, the loading motor (not shown) is rotated reversely and the adapter chassis 14 is raised by the operation opposite to the loading operation. When the raised adapter chassis 14 is detected, the drive motor (not shown) is rotated reversely and the slider 6 moves to the initial position by the same operation as in the case of ejecting the large-sized cassette 3. When the adapter chassis 14 is raised, the first and second drawing-out arms 22 and 23 are driven in the direction opposite to the above described direction, whereby the magnetic tape 1a returns to the initial position. The locking of the lock mechanism (not shown) of the housing 19 is cancelled by means of a solenoid (not shown). As a result, the housing 19 is raised by means of the up spring 20 to open the cassette cover 19 for the small-sized cassette. Thus, the small-sized cassette 1 is ready to be taken out.
While the small-sized cassette 1 is not inserted in the housing 19, the switch for detecting the insertion of the small-sized cassette 1 is not operated even if the housing 19 is depressed to be locked in the adapter chassis 14. In consequence, the first and second tape drawing-out arms 22, 23 are not driven, and the adapter chassis 14 is not lowered. Thus, when the small-sized cassette 1 is not used, the housing 19 is depressed and locked in the adapter chassis 14, whereby the cassette cover 15 can be closed. At this time, since the adapter chassis 14 is not lowered, the large-sized cassette 3 can be inserted.
FIG. 6 schematically shows such a cassette control unit of a magnetic recording and reproducing apparatus in which plural types of cassette of different sizes can be selectively loaded for recording and reproduction without using a cassette adapter. Referring to FIG. 6, when the large-sized cassette 3 is inserted from a front cabinet 34 in the direction shown by the arrow I, it is loaded in the direction shown by the arrow II, whereby it is set in a prescribed position. In order to load the small-sized cassette 1, the small-sized cassette 1 is inserted from an upper cabinet 24 in the direction shown by the arrow III and it is depressed in the direction shown by the arrow IV, whereby it is set in the adapter chassis 14. Then, after the magnetic tape la is drawn out in the direction shown by the arrow V, the small-sized cassette 1 is lowered in the vertical direction shown by the arrow VI, whereby it is set in a prescribed position.
In the above described cassette loading mechanism, the inlet opening of the large-sized cassette exists on the front surface of the magnetic recording and reproducing apparatus. The inlet opening of the small-sized cassette exists on the upper surface of the magnetic recording and reproducing apparatus. Since the inlet openings of the large-sized cassette and the small-sized cassette are located in the different positions, the loading operation for the cassettes is not simple. Particularly, in the case where the magnetic recording and reproducing apparatus is used in a fixed manner in a rack or the like, it is sometimes difficult to insert and take out the small-sized cassette since the small-sized cassette inlet opening exists on the upper surface of the magnetic recording and reproducing apparatus. In addition, a large limitation is imposed on the design of the magnetic recording and reproducing apparatus because of the small-sized cassette inlet opening located on its upper surface. Further, since it is necessary to manually open or close the housing 19 at the time of loading or removing the small-sized cassette without association of movement of the adapter chassis 14 or the like, operability in loading or removing the small-sized cassette is not good.